As the cost of energy or fuel (e.g., electrical charge, gasoline, kerosene, natural gas or diesel fuel) inevitably increases over the next few decades, vehicle operators will become more concerned about consumption of fuel in moving from a first location, for example, the vehicle present location, to a second location. This will be especially true for a fuel such as electric charge, which is consumed relatively quickly due to the relatively small current capacity of an array of batteries using present technologies, and for which relatively few electrical recharge sources are available as yet. Presently, as many as 12 batteries are needed to provide sufficient electrical charge for a trip of modest length, such as 150 miles. If the day's activities include a series of shorter vehicle trips, it becomes important to determine whether all of these trips can be completed, given the constraint on electrical charge usage.
Several workers have disclosed systems for monitoring energy or fuel use, especially for limited storage capacity systems such as batteries. Examples of these systems are disclosed in U.S. Pat. No. 5,216,623, issued to Barrett et al, No. 5,281,919, issued to Palanisamy, No. 5,303,163, issued to Ebaugh et al, No. 5,315,235, issued to Atherton et al, No. 5,325,048, issued to Longini, No. 5,335,188, issued to Brisson, No. 5,377,114, issued to Gross, and No. 5,600,566, issued to Park.
Other workers have disclosed systems for predicting or estimating, usually in a limited environment, energy or fuel use over a specified time interval. Examples of these systems include U.S. Pat. No. 5,301,113, issued to To et al, No. 5,315,287, issued to Sol, No. 5,317,269, issued to Mills et al, No. 5,321,616, issued to Palladino, No. 5,371,682, issued to Levine et al, No. 5,459,666, issued to Casper et al, No. 5,487,002, No. 5,539,399, issued to Takahira et al, and No. 5,578,748, issued to Brehob et al.
Most of these systems assume a fixed and unchanging environment for prediction purposes and do not take account of the changing conditions a vehicle will encounter over the course of a selected route, such as change in elevation, type of road surface, number of road lanes, local traffic density, vehicle velocity, local temperature, local wind speed and other weather variables. Further, most such systems have no ability to modify a prediction of energy or fuel usage enroute, based upon conditions encountered over an initial portion of a route.
What is needed here is a system that analyzes a proposed vehicle route and proposed time interval of travel and provides a prediction or estimation of the electrical charge or conventional fuel that will be consumed in traveling over that route. Preferably, the system will take account of changes in vehicle elevation and vehicle velocity, expected traffic conditions and traffic density and expected or actual weather conditions in providing this prediction or estimation. Preferably, this system will allow a re-estimation of fuel usage enroute, after an arbitrary portion of the route has been covered.